1. Field of the Invention
The present invention relates to a fluid discharging device for sucking, measuring and discharging a fluid such as a liquid, gas and the like, and can be utilized particularly in a dispenser for repeatedly discharging each constant amount of fluid or in a pump for continuously feeding a fluid.
2. Description of the Related Art
Up to now, devices in various forms are known as a fluid discharging device (pump or dispenser), and the present applicant has proposed pumps of a plunger type disclosed in Japanese Patent Laid-Open Publication No. Hei 2-55,878 and Japanese Patent Laid-Open Publication No. Hei 2-230,975, and a diaphragm pump disclosed in Japanese Patent Laid-Open Publication No. Hei 7-35,046 as a pump capable of discharging even a very small amount of fluid with high accuracy.
These fluid discharging devices each comprise a suction passage opening and closing valve for opening and closing a suction passage to suck a fluid, an outlet opening and closing valve for opening and closing an outlet to discharge the fluid and a discharging member for discharging the fluid, arrange the outlet opening and closing valve, the discharging member and the suction passage opening and closing valve in the shape of concentric circles in the order of the outlet opening and closing valve, the discharging member and the suction passage opening and closing valve from the inside to the outside, and comprise a driving mechanism for driving the outlet opening and closing valve, the discharging member and the suction passage opening and closing valve so that they operate respectively in their specified action manners.
A sucking operation in these fluid discharging devices closes an outlet opening and closing valve, opens a suction passage opening and closing valve, moves a discharging member away from the outlet in this state, and makes a space formed between the outlet and the discharging member suck a fluid into it.
And a discharging operation of it closes the suction passage opening and closing valve after suction of a fluid and thereby measures a specified amount of liquid to be discharged, and thereafter opens the outlet opening and closing valve, moves the discharging member to the outlet side and discharges the fluid, and finally closes the outlet opening and closing valve to complete the discharging operation.
In such a way, since each of these fluid discharging devices is provided with a suction passage opening and closing valve and an outlet opening and closing valve, cuts off the communication between the suction passage and the outlet during the period from a fluid sucking operation to a discharging operation and performs a measuring operation for measuring an amount of liquid to be discharged, it can adjust even a very small amount of fluid to be discharged with high accuracy.
In these fluid discharging devices, however, since it is necessary to drive separately the respective suction passage opening and closing valve, outlet opening and closing valve and discharging member described above, it is necessary to provide three driving units. Due to this, there has been a problem that the inside structure of a fluid discharging device becomes so complicated that it is difficult to be made small-sized.
And these fluid discharging devices are utilized to discharge an extremely small amount of adhesive, drug and the like in a semiconductor production line and the like, and since it is possible to suppress the interval or space between a number of fluid discharging devices arranged in parallel to the minimum and improve the efficiency of production if a fluid discharging device itself can be made small-sized, it has been intensely desired to make a fluid discharging device small-sized.
An object of the present invention is to provide a fluid discharging device capable of discharging even a very small amount of fluid with high accuracy and being made simple in structure and small in size.
Another object of the present invention is to provide a fluid discharging device capable of preventing a fluid from leaking outside the fluid discharging device and capable of being manufactured in low cost even in case of making it chemical-resistant.
The present invention is characterized by a fluid discharging device comprising a pump member, a valve member, and a suction passage and an outlet capable of communicating with a measuring space to be closed by the pump member and the valve member, wherein;
said valve member is provided with said outlet and is provided so as to be movable forward and backward in the axial direction of the outlet relative to the pump member, and this valve member is provided with a suction passage opening and closing portion capable of closing or opening said suction passage by being attached to or detached from said pump member with the forward or backward movement of it, and
said pump member is provided with an outlet opening and closing portion capable of closing or opening the outlet by being attached to or detached from the outlet of the valve member and a measuring portion which is arranged in the shape of a concentric circle outside this outlet opening and closing portion and is capable of changing the volume of a measuring space by being moved forward and backward relative to said measuring space; and
said fluid discharging device is provided with;
an outlet opening and closing means which can close and open the outlet by moving said outlet opening and closing portion forward and backward relative to the outlet, and can open the suction passage by detaching the suction passage opening and closing portion of the valve member from the pump member through energizing said valve member toward the outlet,
a measuring portion moving means which is arranged in the shape of a concentric circle outside the outlet opening and closing means and can change the volume of the measuring space by moving said measuring portion forward and backward relative to the valve member,
an energizing means for closing the suction passage by pressing said suction passage opening and closing portion against the pump member through energizing said valve member toward the pump member, and
a driving means for driving said outlet opening and closing means and said measuring portion moving means respectively in their specified action manners.
In such an invention as described above, since a valve member having an outlet formed in it which has not been moved hitherto is provided so as to be movable forward and backward in the axial direction of the outlet and this valve member is moved forward and backward by an energizing means and an outlet opening and closing means, the outlet opening and closing means for moving the outlet opening and closing portion can be also utilized for moving the suction passage opening and closing portion.
Due to this, while it is necessary to provide three driving units in the prior art, it is enough to provide only two driving units in the present invention and it is possible to make a fluid discharging device simple in structure and small in size.
Further, since it is provided with a suction passage opening and closing portion and an outlet opening and closing portion, it can perform a measuring operation for measuring an amount of liquid to be discharged by cutting off the communication between the suction passage and the outlet during the period from a fluid sucking operation to a discharging operation, and can discharge even a very small amount of fluid with high accuracy.
In the present invention, it is preferable that said pump member is formed out of a diaphragm being made into a thin film in the central side and being made thick in thickness in the peripheral side, an outlet opening and closing portion and a measuring portion formed on the circumference having this outlet opening and closing portion as its center are provided on the thin film part, and a flat seal portion against which the outlet opening and closing portion of said valve member is pressed is formed on said peripheral part made thick in thickness, an said valve member is formed into one body with a diaphragm being made into a thin film in its peripheral side and being made thick in its central side and is fixed immovably to said pump member in its peripheral part, and an outlet is formed in said thick part being continuous to this peripheral part through the thin film, and this thick part is made movably forward and backward relative to said pump member by the deformation of said thin film part.
Forming each of a pump member and a valve member out of a diaphragm makes unnecessary the hermetic sealing between movable members such as an outlet opening and closing means, a measuring portion moving means and the like, improves the hermetic-sealing ability and thereby prevents a liquid from leaking outside the fluid discharging device and reduces the number of members to be in contact with liquid and therefore leads to reduction in manufacturing cost in case of making the fluid discharging device chemical-resistant.
And since the arrangement of an outlet opening and closing portion, an outlet opening and closing means for moving a measuring portion and a measuring portion moving means in the shape of concentric circles makes uniform the displacement in movement of each part of a diaphragm from the central part and thereby stabilizes the operation of them and makes it possible to control the displacement with high accuracy, a high-accuracy discharge is made possible even in case of a very small amount of fluid to be discharged.
In the present invention, it is preferable that the outlet opening and closing portion of said pump member is made thicker in thickness than the other thin film part and said measuring portion is formed by bending the thin film part.
If the device is formed in such a way, when the outlet opening and closing portion and the measuring portion are moved by the respective opening and closing means and moving means, the other thin film parts are surely deformed and thereby the outlet opening and closing portion and the measuring portion can be separately and smoothly moved. Therefore, it is possible to stabilize the operations of the outlet opening and closing portion and the measuring portion and also improve a fluid discharging operation in accuracy.
In the present invention, it is preferable that the outlet opening and closing portion and the flat seal portion of said pump member, and the outlet opening and closing portion of said valve member and the opening end face part of the outlet against which said outlet opening and closing portion is pressed are finished by lapping.
Making each of these parts have a finished face by lapping makes it possible to secure a necessary and sufficient sealing ability only by pressing them against each other. Further, in the present invention since the contact face of each part is a flat seal, a lapping process can be performed low in cost and high in accuracy and a high-accuracy discharging operation can be performed even in case of a very small amount of fluid to be discharged.
In the present invention, it is preferable that said driving means is composed to drive said outlet opening and closing means and said diaphragm moving means so as to perform;
a sucking operation of, in a state where the outlet is closed by pressing said outlet opening and closing portion against the valve member, sucking fluid by opening the suction passage by detaching the suction passage opening and closing portion of the valve member from the pump member and making the measuring space larger in volume by moving the measuring portion of the pump member away from the valve member,
a measuring operation of measuring the fluid to be discharged by, after this sucking operation, closing the suction passage through pressing the suction passage opening and closing portion of the valve member against the pump member, and
a discharging operation of discharging the fluid by, after this measuring operation, opening the outlet by detaching the outlet opening and closing portion of the pump member from the outlet and moving the measuring portion of the pump member so as to become close to the valve member.
Such a driving means can be formed out of, for example, a piezoelectric device, a fluidic cylinder, a motor, a cam, a solenoid and the like.